As details emerge from Nairobi, especially on the identities and stories of the terrorists who are alleged to be American, the public in the United States is going to need clear answers to some very hard questions.

The families of the victims in Kenya will also want to know how America has turned into a jihadist-exporting country.

In May, four Minnesota men were sentenced to prison for helping recruit young men in Minnesota to travel to Somalia and fight for al-Shabab.

Investigators believe about 20 young, ethnic Somali men left Minnesota from 2007 to 2009 to go to Somalia to join the African franchise of al Qaeda.

Three of the men sentenced in May who had cooperated with investigators were each sentenced to three years and a fourth man was sentenced to 12 years in prison.

“These defendants, by providing material support to a designated terrorist organization, broke both the law and the hearts of family members across the Twin Cities,” U.S. Attorney B. Todd Jones said in a statement quoted by the Associated Press in a May story, but the trial and sentencing received little media play.

You can be assured it will now, as will the identities of the rest of the missing Minnesotans and all who aided in their radicalization.

In 2006, the late John Updike published his 22nd novel, “Terrorist,” which is the story of how one young American became radicalized and absorbed into a terrorist organization.

A society as open as ours, and with many malls as vulnerable as Nairobi’s Westgate shopping center in every city of any size, has got to expect that eventually the same sort of horror will come here.

The young radicals on their killing spree in Kenya have stories as detailed as Updike’s fictional would-be terrorist from New Jersey, Ahmad Mulloy. Updike’s teenager-turned-terrorist was guided by another fictional character, Shaikh Rashid.

For each of the real life murderers, there is a chain-of-custody of their malign beliefs. Good journalists in the Twin Cities will verify if the claims of al Shabab are true, and if they are, they will start digging.

Are the four men in federal prison responsible at least in part for this awful carnage in Kenya? If so, will we be extraditing them to Kenya to face the justice system there, and the consequences of their counseling of the American teens-turned-killers.

Perhaps these four men have nothing to do with the three said to be on the killing spree in Nairobi. Perhaps it is all al Shabab propaganda.

But journalism’s job is to find out the truth, and to make sure the story is told and patterns detected so that everyone, especially law enforcement in partnership with patriotic Somali immigrants and responsible Muslim imams, work to prevent this from happening again.

The carnage is horrible and the aftermath will be terrible to look at, much less examine in detail. But it has to be done. Watch and see if the Minneapolis Star Tribune wins the Pulitzer in front of it for telling us where these young killers came from and how they turned out so terribly, terribly cruel.